Screw conveyer



'Patented May 6, 1930 I UNITED STATES PATENT OFFICE JAN ADRIAAN BARTEL SMIT, OF DEVENTER, NETHERLANDS, ASSIGNOR TO NAAM- LOOZEVENNOOTSCHAP INTERNATIONALE OXYGENIUM MAATSCHAPPIJ NOVADEL,

0F DEVENTER, NETHERLANDS i SCREW CONVEYER Application led November 3, 1927, Serial N'o. 230,855, and in the Netherlands May 13, 1937.

This invention relates to conveyers for dispensing finely divided powderous material and more particularly to a feeding conveyer for ensuring continuous and regu ar 'How of the material in constant relatively small quantities.

In apparatus for this purpose usually employed, it has been found very diliicult to obtain a regular and uniform addition of such materialon a constant feed over any given period. This diiculty has been especially realized when adding `solid substances to flour, either for the purpose of bleaching, improving the baking qualities or for manufactu-rin flour containing baking powder. It is di cult to regulate the How of such powderous-material through a restricted aperture, the material tending to choke the aperture under certain conditions and at other times to. flow intermittently and in various amounts.

It is an object of the present invention to provide a conveyer in the form of a helical wire having projections thereon for improving the conveying action and for making the delivery more regular.

Quite against expectation, such a wire does not rotate in the mass without conveying the powder; on the contrary the displacement of the substance to the outlet takes place regularly and continuously, the substance being dispensed in a very loose state so that its i A particles do not adhere together.

It is a matter of course that the thickness rof the wire and the pitch of the windings will be determined by the diameter of the screw, the rate of feed and the nature of the substance to be conveyed.

The invention will be understood from the following description of a complete feeding apparatus containing the improved conveyer taken in connection with the accompanying drawings in which Figure l is an elevation, partly in section, of a hopper provided with a preferred form of the conveyer wire; Figure 2 is a modification illustrating additional means on the wire for conveying the mass, and

Figure 3 is a vertical cross section taken on' the line AB of Figure 2.

A hopper l is provided with an inclined bottom 2, the conveyer 4 rotating in a horizontal passage 3 communicating with the 55 hopper at 8. The conveyer is rotated by a suitable driving device such as a spur wheel v5 on the shaft 6. The material 7 within the hopper l is delivered into the horizontal passage 3 and conveyed by the rotating helical 60 wire to the outletwhere it is delivered in regular constant relatively small quantities.

It has been found that excellent results have been obtained with a wire having a diameter of 2 mm., the pitch of the helix bee5 ing 10 mm., and the diameter of the helix 16 mm. A continuous and regular flow ofy material was obtained when the conveyer rotated at the rate of ten revolutions per minute.

not, however, Aseem to be dependent on the pitch of the windings. It has moreover been found that the regularity of the feed is improved if there is arranged at the last con volution of the screw one or more pins such` as 9, these pins being arranged parallel with the axes of the spindle yand conveyer and are arranged within the enveloping surface of the helix. The pins 9 have nearly the same thickness as the spiral wire and may be of so a length of for example 5 to 20 millimetres.

`While the preferred form of the helix is circular, satisfactory results have been obtained using a helical wire of elliptical or angular formation, also the wire may be rovided with local enlargements or protu er- Vances such as l0, also pins or such like which Monel-metal and such like have successfully been used. If the substance be of a corrosive nature it is necessary to give the wire a coating of a resistant material, or to make the wire from a resistant material. From the above description it will be understood that The quantity of material delivered does 70 The material from which the 90 the improved screw conveyer has considerable advantages owing to its extreme simplicity following from its bearing at one side onlyV while furthermorethe lack of a central 5 shaft makes its construction very simple.

Although a preferred embodiment of the invention has been described, it is to b'e understood that it may be modified within the limits of the appended claim. Having now described my invention, what I claim :1s-new and desire to secure by Let' ters Patent is A' device for feeding powderous material, comprising in combination, a receptacle containing the said material, and having a discharge opening, a rotating helical Wire conveyer adjacent such opening, andone or more cylindrical pins at one end of the said Wire arranged Within the envelopingr surface of 42f, said helical wire and parallel with the axis thereof, for the purpose of delivering the powderous material in uniform and regular quantity.

In testimonywhereof I have signed my name to this specification.

JAN ADRIAAN BARTEL SMIT. 

